Explicație pas cu pas:
a) (2/5)^2x = (2/5)^6
2x = 6
x=3
b) (1/9)^(x+5) = (1/9)^10
x + 5 = 10
x = 5
c) (3/7)^x :(3/7)^3 = (3/7)^2
(3/7)^(x-3) = (3/7)^2
x - 3 = 2
